Single-Molecule Spectroscopy on Polythiophene Conjugated Polymers and Aggregates: Towards Structure - Function Relationships

聚噻吩p-共轭聚合物是一类非常受欢迎的有机功能材料，并被用于新型光电器件，如光伏电池和场效应晶体管。尽管这种共轭聚合物的应用取得了成功，但其电子结构仍不完全清楚。特别地，电子激发态的特性是要讨论的。在这个项目中，我们将采用互补的单分子技术，即荧光和荧光激发光谱以及时间分辨光谱，来研究单个多噻吩链的光物理性质，作为它们的长度，它们的局部环境，它们的构象和温度的函数。这将有助于揭示这种技术上高度相关的材料类别的电子和几何特性之间的清晰相关性。最后，我们还将研究单聚噻吩聚集体的光物理性质，这对有机器件的性能起着重要作用。这里的目的是揭示链内和链间相互作用之间的微妙相互作用，这是理解这些聚集体内部和之间（电荷和能量）传输过程的关键。

Polythiophene p-conjugated polymers are a very popular class of organic functional materials and are exploited in novel optoelectronic devices, such as photovoltaic cells and field-effect transistors. Despite the successful applications of this conjugated polymer its electronic structure is still not fully understood. In particular the character of the electronically excited states is subject to discussion. In this project we will employ complementary single-molecule techniques, i.e. fluorescence and fluorescence excitation spectroscopy as well as time-resolved spectroscopy, to study the photophysical properties of individual polythiophene chains as a function of their length, their local environment, their conformation, and the temperature. This will allow to unravel clear correlations between the electronic and geometric properties of this technologically highly relevant material class. Finally, we will also investigate the photophysics of single polythiophene aggregates, that play an important role for the performance of organic devices. Here the aim will be to reveal the subtle interplay between intra- and inter-chain interactions that is key to understand (charge and energy) transport processes within and between such aggregates.